The photothermal stability study of silica-coated CsPbBr3 perovskite nanocrystals

The lead halide perovskite (LHP) semiconductor material has many outstanding advantages and was widely used light-emitting device, however their low stability severely limited the practical application and further commercialization. We proposed a two-step method for synthesizing CsPbBr 3 /SiO 2 composites to improve the stability of CsPbBr 3 perovskite nanocrystals (PNCs). The synthesized CsPbBr 3 /SiO 2 composites can maintain photothermal stability, and also have a narrower photoluminescence (PL) bandwidth of 20.2 ​± ​0.26 ​nm, and the PL peak (518 ​nm) hardly shifted during the two-step synthesizing process. Through the temperature-dependent PL spectroscopy, we show that the CsPbBr 3 /SiO 2 composites have a high exciton binding energy 50.0 ​meV and longitudinal optical phonon energy 80.1 ​meV, suggesting that the robust excitons exist in CsPbBr 3 /SiO 2 composites. The improved stability of the composites is demonstrated by exposure to harsh environments such as laser irradiation, heating and water. These findings are greatly significant for further applications of CsPbBr 3 PNCs in optoelectronic devices.